Fossil

/*
** These two types are used only by the expression module, where
** the expression module means the Th_Expr() and exprXXX() functions.
*/
typedef struct Operator Operator;
struct Operator {
  const char *zOp;
  int nOp;
  int eOp;
  int iPrecedence;
  int eArgType;
};
typedef struct Expr Expr;
struct Expr {
  Operator *pOp;

*/
#define ARG_INTEGER 1
#define ARG_NUMBER  2
#define ARG_STRING  3

static Operator aOperator[] = {

  {"(",  1, OP_OPEN_BRACKET,   -1, 0},
  {")",  1, OP_CLOSE_BRACKET, -1, 0},

  /* Note: all unary operators have (iPrecedence==1) */
  {"-",  1, OP_UNARY_MINUS,    1, ARG_NUMBER},
  {"+",  1, OP_UNARY_PLUS,     1, ARG_NUMBER},
  {"~",  1, OP_BITWISE_NOT,    1, ARG_INTEGER},
  {"!",  1, OP_LOGICAL_NOT,    1, ARG_INTEGER},

  /* Binary operators. It is important to the parsing in Th_Expr() that
   * the two-character symbols ("==") appear before the one-character
   * ones ("="). And that the priorities of all binary operators are
   * integers between 2 and 12.
   */
  {"<<", 2, OP_LEFTSHIFT,      4, ARG_INTEGER},
  {">>", 2, OP_RIGHTSHIFT,     4, ARG_INTEGER},
  {"<=", 2, OP_LE,             5, ARG_NUMBER},
  {">=", 2, OP_GE,             5, ARG_NUMBER},
  {"==", 2, OP_EQ,             6, ARG_NUMBER},
  {"!=", 2, OP_NE,             6, ARG_NUMBER},
  {"eq", 2, OP_SEQ,            7, ARG_STRING},
  {"ne", 2, OP_SNE,            7, ARG_STRING},
  {"&&", 2, OP_LOGICAL_AND,   11, ARG_INTEGER},
  {"||", 2, OP_LOGICAL_OR,    12, ARG_INTEGER},

  {"*",  1, OP_MULTIPLY,       2, ARG_NUMBER},
  {"/",  1, OP_DIVIDE,         2, ARG_NUMBER},
  {"%",  1, OP_MODULUS,        2, ARG_INTEGER},
  {"+",  1, OP_ADD,            3, ARG_NUMBER},
  {"-",  1, OP_SUBTRACT,       3, ARG_NUMBER},
  {"<",  1, OP_LT,             5, ARG_NUMBER},
  {">",  1, OP_GT,             5, ARG_NUMBER},
  {"&",  1, OP_BITWISE_AND,    8, ARG_INTEGER},
  {"^",  1, OP_BITWISE_XOR,    9, ARG_INTEGER},
  {"|",  1, OP_BITWISE_OR,    10, ARG_INTEGER},

  {0,0,0,0,0}
};

/*
** The first part of the string (zInput,nInput) contains an integer.
** Set *pnVarname to the number of bytes in the numeric string.
*/
static int thNextInteger(

  int nExpr,                /* Number of bytes at zExpr */
  Expr ***papToken,         /* OUT: Array of tokens. */
  int *pnToken              /* OUT: Size of token array */
){
  int i;

  int rc = TH_OK;
  int nNest = 0;
  int nToken = 0;
  Expr **apToken = 0;

  for(i=0; rc==TH_OK && i<nExpr; ){
    char c = zExpr[i];
    if( th_isspace(c) ){                                /* White-space     */
      i++;

            pNew->nValue = iEnd+1-i;
          }
          break;
        }

        default: {
          int j;
          const char *zOp;
          for(j=0; (zOp=aOperator[j].zOp); j++){
            int nOp = aOperator[j].nOp;
            int isMatch = 0;
            if( (nExpr-i)>=nOp && 0==memcmp(zOp, &zExpr[i], nOp) ){
              isMatch = 1;
            }
            if( isMatch && aOperator[j].eOp==OP_OPEN_BRACKET ){
              nNest++;
            }else if( isMatch && aOperator[j].eOp==OP_CLOSE_BRACKET ){
              nNest--;
            }
            if( nToken>0 && aOperator[j].iPrecedence==1 ){
              Expr *pPrev = apToken[nToken-1];
              if( !pPrev->pOp || pPrev->pOp->eOp==OP_CLOSE_BRACKET ){
                continue;
              }
            }

            if( isMatch ){
              pNew->pOp = &aOperator[j];
              i += nOp;
              break;
            }
          }
        }
      }

        nToken++;
      }else{
        Th_Free(interp, pNew);
        rc = TH_ERROR;
      }
    }
  }

  if( nNest!=0 ){
    rc = TH_ERROR;
  }

  *papToken = apToken;
  *pnToken = nToken;
  return rc;
}

/*